Brake control means



April 23, 1940. I FARMER 2,198,030

BRAKE CONTROL MEANS Filed July .29, 1938 v lNVENT OR CLYDE c. FAEMEEATTORNEY Patented A an 23, 1940 I Clyde 0. Farmer, Pittsburgh, Pa.,assignor to The Westhlghonse Air Brake Company, Will-- merding, Pa, acorporation of Pennsylvania Application July 29-, 1938, Serial No.221,951

9 Claims. .(cl. 303 21 This invention relates to brake control meansmined low pressure, the time required for such for vehicles, such asrailway cars or trains, and; reduction in brake cylinder pressure beinglonger particularly to brake control means adaptedto than the timerequired for the slipping wheel function automatically in response tothe slipto accelerate back to vehicle or rail speed. This 5 ping of anindividual wheel and axleunit for prior application also discloses anarrangement releasing the brakes on the slipping wheels to which isnormally ineffective to restrict the rate prevent sliding thereof andfor controlling the of supply of fluid under pressure to a brakejcylreapplication of the brakes on the slipping wheeL- inder and whichis automatically conditioned As is well known, when the brakesassociated when a vehicle wheel slips so'as torestrict the m with avehicle wheel are applied with sufilcient rate of resupply to the brakecylinder "eficcted rm force to exceed the limit of adhesion between theafter the slipping wheel returns fully to the ve tread or rim of thewheel and the road or rail hicle or rail speed. 1 I surface, the wheelrapidly decelerates toward a My present invention is adapted toaccomplish locked or non-rotative condition. If the braking the samedesirable objectives as the arrangement force on a slipping vehiclewheel is rapidly redisclosed in my priorapplication but by simplified 5duced at the instant the wheel. begins to slip, the and improved means.I

vehicle wheel will cease to decelerate and accel- It is possible thateven with controlled reap crate back toward a rotative speedcorresponding plication of the brakes following .a slippingwheel tovehicle or rail speed without actually reaching condition, recurrence ofwheel slipping may occur the locked or non-rotative condition. in caseswhere the adhesion or rolling friction For convenience, the term slip orslipping between a vehicle wheeland the rail is v'ery low. is appliedherein to the rotation of a vehicle wheel In order therefore, to furtherinsureagainst res at a speed less than a rotative speedcorrespondcurrent slipping cycles, my iIIVBIItiOlltfllIthBI iningto'vehicle or rail speed at a given instant, cl'udes an arrangement forautomatically effectwhether the wheel is decelerating or accelerating.ing sanding of the rails, and a consequent 'im- 5 The term slide orsliding is employedherein movement in the adhesion between the wheel todesignate the dragging of the vehicle wheel and the rail, uponinitiation of 'slipping offa along a road surface or rail in'a locked or"non wheel and for automatically terminating the sandrotative state.Thus it should be understood that ing after a predetermined lapse oftime.

a slipping wheel is one that is rotating whereas My invention includes acontrol valveffmechano a sliding wheel is one that is' not rotating. Inism of novel construction adapted to efiect-the If the brakes on aslipping wheel are reapplied release of the brakes inresponse to awheelj'slipwhile the wheel is accelerating back toward veping condition,to prevent reapplication ofjthe hicle or rail speed following theautomatic rebrakes until the brakecylinder pressure reduces lease of thebrakes and a sufficientidegreeof below a certain uniformlowpressure,to'control application is attained, the wheel may again the rateofreapplication, and to control auto decelerate toward a locked ornon-rotative state, matic sanding of the rails. In order to prevent,"asmuch as possible, repeated It is accordingly an object of my inventionto slipping cycles, it is desirable to avoid reapplying provide aiiuidpressure brake. equipment'lior ve- I 0 the brakes on aslippingwheel until it returns hicles, such as railway carsor trains, and in-49,

fully to a speed corresponding to vehicle speed. eluding novel means forinstantly and rapidly For the same reason, it is also desirable not toreleasing the brakes ,on a wheel that 'begins'to restore the originaldegree of application of the slip to prevent sliding of the wheel,and-also for f brakes which initiates slipping of .a Wheel. preventingthereapplication of the brakes on the 5 In my prior copendingapplication,'Seria1 No. slipping wheel until it returns completelyto ve-209,648, filed May 24, 1938, and assigned to the hicle or rail speed. aassignee of this application, there is disclosed Another object of myinvention is to. provide an equipment for effecting the above desirablea fiuid pressure brake equipment of the character objectives. In myprior application, Serial No. Y indicated in the foregoingobject andincluding 59 209,648, an arrangement is provided whereby means,normallyinefiective to control the rate 150 reapplication of the brakes on awheel following of reapplication of the brakes, adapted to .beren- 'Qslipping thereof iscontrolled automatically by deredefiective, when awheel, slips, to control the brake cylinder pressure so as to insureprevention rate of reapplication of the brakes on the'slipping ofreapplication of the brakes until the brake wheel. 4

cylinder pressure has reduced below a predeter+ A further object otmyinvention ;is=;to provide mm. orrlcr: f

shown in the single figure of the accompanying drawing. I

Description of equipment The equipment comprising one embodimentof myinvention, as shown in the single figure in the accompanying drawing,includes one or more brake cylinders H for effecting application andrelease of the brakes associated with an individual wheel and axle unitor a plurality of wheel and axle units, not shown, a source of fluidunder pressure hereinafter called the main reservoir |2, a manuallyoperableself-lapping brake valve l3, a straight-air pipe I 4 thepressure in which is controlled by the brake valve |3, a brake cylinderpipe l5 through which fluid under pressure is supplied from thestraight-air pipe l4 to the brake cylinder l, a control valve mechanism|6 interposed in the brake cylinder pipe l5 and controlled by a magnetvalve device H and a wheel-slip responsive device ll! of the rotaryinertia type associated with the same wheel and axle unit as is thebrake cylinder l. The equipment further comprises a pressure operatedswitch IS, a plurality of sanding devices 2|, 2. sanding reservoir 22, asanding control valve device 23 and a timing reservoir 24 for timing theoperation of the sanding control valve device 23.

Considering the parts of the equipment in greater detail, the brakevalve I3 is of the type described and claimed in Patent No. 2,042,112 ofEwing K. Lynn and Rankin J. Bush. In view of the detailed descriptiongiven in the patent, a functional description of the brake valve 3 isdeemed suifioient for the purposes of the present application. When theoperating handle 25 of the brake valve |3 is in its-normal releaseposition, the brake valve is conditioned to vent the straight-air pipe Mto atmosphere. When the handle 25 is shifted horizontally out of itsnormal release position into a so-called application zone, the brakevalve is conditioned to establish communication through which fluidunder pressure is supplied from a supply pipe 26, connected to the mainreservoir l2, to the straight-air pipe l4, the brake valve beingautomatically self-lapping to establish a pressure in the straight-airpipe |4 substantially proportionate to the displacement of the operatinghandle 25 out of its normal release position.

Should the pressure in the straight-air pipe l4 tend to reduce due toleakage or for other reasons,

from a pressurecorresponding to the position of the operating handle,the brake valve is automatically operative to supply further fluid underpressure to the straight-air pipe to restore and maintain a pressuretherein corresponding to the position of the brake valve handle. Thispressure maintaining feature of the brake valve |3 is of importance inconnection with the reapplication of the brakes as will be describedhereinafter. It

- piston 31.

cover sections 32 and 33, respectively, adapted to be secured to themain section 3| in sealed relation by gaskets 33a and 33b, and suitablescrews or bolts, not shown. Embodied in the casing of the control valvemechanism l6 are a release and reapplication valve device 34 hereinafterreferred to as the release valve device, and valve device 35 forcontrolling the rate of resupply of fluid under pressure to the brakecylinder and hereinafter referred to as the reapplication controldevice. '1 l {"1 The release valve device 34 comprises an annular piston31 having a tubular stem 38, extend ing to one sidethereof, the outerend of which is closed and formed as a piston valve 39, hereinafterdesignated the vent valve. Also formed on the outside of the hollow stem38 at a point between the vent valve 39 and the piston 31 is a piston4|. The piston 31 operates in a suitable bore 42 formed in the casingsection 3| and the vent valve 39 and piston 4| operate in a bore '43 ofsmaller diameter than the bore 42 and in coaxial alignment therewith.

The bore 42 opens at the face of the casing section 3| covered by theend section 32, a chamber 44 being thus formed between the piston 3'!and the casing section 32 at the upper side of the Interposed betweenthe end casing section 32 andthe piston 31 within chamber 44 is a coilspring 45, one end of which engages in a suitable recess 46 in thecasing section 32 and the other end of which is received in and bearsagainst the closed end of the hollow stem 38 of the piston 31. Thespring 45 normally yieldingly urges the piston 31 downwardly to effectseating of the vent valve 39 on an annular rib seat 41 which surroundsan exhaust port 48. An annular gasket 49 is inset in the face of thevent valve 39 for effecting sealing engagement with the annular rib seat41.

Formed in the casing section 3|, between the pistons 3! and 4| of therelease valve device 34 and in surrounding relation to the stem 38, isan annular chamber 5| to which the brake cylinder H is connected througha passage 52 and one section of the brake cylinder pipe l5. Chamber 5|communicates withthe chamber 44 above the piston 31, when the piston 31is in its normal position shown, through a branch passage 53 of thepassage 52, the passage 53 containing a restriction or choke 54. Anotherbranch passage 55 of the passage 52 opens into the bore 43 at a pointimmediately above the vent valve 39 when the vent valve 39 is seated onits annular rib seat 41.

The choke 54 is of such size that when fluid under pressure is suppliedinto the annular chamber 5| and thus to the brake cylinder H, in themanner to be hereinafter described, chamber 44 at the upper side of thepiston 31 becomes sufflciently rapidly charged through the choke 54 thatthe spring 45 is effective to exert a sufficient force on the piston 31:to maintain the vent valve 39 seated on its annular rib seat 41. Withthe annular chamber 5| and brake cylinder charged with fluid underpressure, a sudden reduction of the pressure of the chamber44, as byventing in the manner hereinafter described, creates a sufficientdifferential fluid pressure force on the piston 31 to cause it to beshifted upwardly against the yielding resistance of spring 45 until anannular rib 56 formed on the upper face of the piston 31 engages aportion of the gasket 3301. between the casing sections 3| and 32, whichserves as a gasket seat.

When the piston 31. is shifted upwardly into seated relation on gasket33a, the vent valve 39 is shifted upwardly to a sufficient degree toestablish communication "between. the passage 55 and and the pressure inthe-brake cylinder II is effective to exert a sufiicient force inchamber 5| onthe lower side ofthe piston 37 to overcome the spring 45,the piston 3'! remains in its upper seated position. Spring 45 is ofsuch strength.

that when the pressure in the brake cylinder acting to maintain thepiston 3'! in its upper seated position reduces to a certain uniform lowpressure, such as fivepounds per square inch, the spring becomeseffective to shift the piston 31.

. downwardly to reseat the ventvalve 39 on its between the supplypassage 56 and the annular.

annular rib seat 4? and restore the connection chamber 5|.

The reapplication control device 35 comprises a valve piston 6 I, avalve 62 hereinafter called the sanding valve, and an exhaust valve .63,all of which are arranged to be operated bya piston 64.

. The valve piston (ii .of the reapplication control device 35 is guidedin a suitable bore 65, formed in the casing section 32, and extends intoa chamsmall passage 19 having a choke element 1| therein. An annular ribseat 12 is formed on the wall 68 in surrounding relation to the bore 69,and the valve piston 6| is adapted to seat on rib-seat [2 to closecommunication through the passage 59 from the chamber 66 to the chamber61, thereby. restricting communication between the chambers to thepassage 18 containing the choke element H. An annular gasket 13 is insetin the face of the valve piston 6! for effecting sealing engagement'withthe annular rib seat 12. Interposed between the casing section 62and the back side, of the valve piston 61 is a coilspring M which iseffective to urge the valve piston 61 downwardly toward seated relationon the annular rib seat '12.

The piston 64 operates in a suitable bore I5 in the casing section 3|and has a hollow stem '16, projecting to one side of the piston andclosed at the outer end thereof which stem operates in a suitable boreTl that .opens into the chamber 67 and is of smaller diameter than thebore l5. Formed at the outer closed end of the hollow stem I6 is a pin18 which projects upwardly through the chamber .61 and passage 69 intothe chamber 66 where it engages the seating face of the valve piston 61.within the annular gasket 13.

The bore 15 inwhlch the piston 64 operates opens at the face of thecasing section 3! covered by the casing section 33 and a chamber 19 isthus formed between the piston 64 and the casing section 33. Interposedbetween the casing :section 33 and the closed end of the hollow stem- 18of the piston 64in the chamber 19 is a coilspring 8! which yieldinglyurges the piston 64 upwardly to effect engagement of the upper end ofthe pin 18 with'the face of the valve piston 6| and unseating of thevalve piston 6| against the yielding resistance of the spring M. r

When the piston 64 is in its upper or raised position unseating thevalve piston 6|, it 'uncovers the opening of'a passage 83into the bore15 atthe lower side thereof, whichpassage 83 is connected to the chamber66 and hasa restriction or choke 82 therein.

When the straight-air pipe I4 is charged with fluid under pressure,fluid under pressure is supplied therefrom through' the one section of.the brake cylinder pipe l5 to the chamber 66 and then past the unseatedvalve piston 6!, through the passage 69, chamber 61, passage 56, annularchamber 5!, passage 52 and the'other section of the brakecylinder pipel5 to the brake cylinder ll. At the same time fluid under pressure issupplied through the passage 83 to the chamber 19 at the lower side ofthe piston 64. Accordingly, since opposite sides of piston 64 aresubject to opposing pressures, spring 81 maintains the piston 64 in itsnormal or raised position unseating the valve piston 6|.

Operation of the piston 64 downwardly is effected by a sudden rapidventing of fluid under pressure from chamber 19 at the lower sidethereof resulting from unseating of the vent valve 39 of the releasevalve-device 34. The outer seated area of the vent valve 39 within thebore '43 is connected to chamber '19 by a short passage 66 which opensinto the bore 15 at a point adjacent the casing section 33. Thus whenthe chambers 6! and 19 on opposite sides of the piston 6 are bothcharged with fluid under pressure, the unseating of the vent valve 39from its annular rib seat 4! vents fluid under pressure from chamber 19at a rapid rate through the passage 86 and exhaust port 48. The higherfluid pressure in chamber 61 acting on the upper side of the piston 64thus shifts the piston downwardly against the yielding resistance ofthespring 8! and causes an annular rib 81 formed on the lower face of thepiston 64 to engageinsealing relation a gasket seat formed on the gasket36b between the casing sections 3| and 33. In shifting downwardly towardthe gasket seat, the piston 64 passes the opening-of the passage 83 andthus cuts off the supply of fluid under pressure from the chamber 66into the chamber 19 and transfers-it to the annular chamber 88 at theupper side of the piston 64, so that the combined pressures of the fluidin chambers 61 and 88 are effective over the entire upper face of pistonand the closed end of stem 76 to thereafter urge the piston positivelyinto seated position on its gasket seat. The passage 86 opens into thebore 15 sufficiently close to the casing section 33 that when the piston64 is seated on the gasket seat 30 of the gasket 33 the passage 66 isnot connected to the annular chamber but remains open to the outerseated area beneath the piston.

The exhaust valve 63 is of the poppet type and is contained in a chamber39 formed in the casing section 33. Valve 63 is yieldingly urgedupwardly into seated relation v on an assooiatedvalve seat formed onthecasing section 33 by a coil spring 9| interposed between the valve and athreaded. plug 90 that is screwed into the outer open end of the chamber89 and has a plurality of vent ports 92 therein. Valve 63 has a flutedstem 93 which is guided in a suitable bore connecting the chamber 89 andthe chamber I9 at the lower side of the piston 64. The endof the flutedstem 93 projects into the chamber I9 and is engaged by the piston 64, ata point within the annular rib 87, so that when the piston shiftsdownwardly into seated position on the gasket seat of gasket 33b, valve63 is unseated.

With the piston 64 seated on its gasket seat and the exhaust valve 33unseated, the chamber I9 at the lower side of the piston 64 is isolatedand vented to atmosphere past valve 63 and through the vent ports 92independently of the vent valve 30 of the release valve device 34. Itwill thus be apparent that with the lower face of piston 54 maintainedsubject to only atmospheric pressure, the fluid pressure in chambers 67and 88 on the upper face of the piston is effective to hold the pistonin seated relation on its gasket seat thereafter as long as the force ofthe fluid pressure in chambers 61 and 08 is suflicient to overcome coilspring BI. The area of piston 04 and the strength of coil spring EU issuch that once the piston is seated on its gasket seat, spring BI isineffective to unseat the piston upwardly from its gasket seat until thefluid pressure in chambers 61 and 88 on the upper face of piston 64reduces below a certain uniform low pressure, such as five pounds persquare inch.

The sanding valve 62 is a double beat valve and it is arranged to benormally urged into seated relation on an associated upper valve seat bya coil spring 94 and shifteddownw'ardly against the yielding resistanceof the spring 9 3 into seated relation on a lower valve seat when thepiston 04 is shifted downwardly to seated relation on its associatedgasket seat. The sanding valve 62 is contained in a chamber to which thetiming reservoir 24 is constantly connected, as by a pipe and passage96, and is guidably supported by means of an annular flange 91 formedthereon which slidably engages in a suitable bore 98 in the casing. Theflange 91 of the valve 02 is provided with suitable grooves 99 thereinso that when the valve 62 is in its upper seated position, communicationis established between a chamber ml, to which the sanding reservoir 22is constantly connected as through a pipe I02, and the chamber 95whereby the timing reservoir 24 is charged to the pressure in thesanding reservoir 22.

The sanding reservoir 22 is constantly charged with fluid under pressurefrom the main reservoir I2, as through a branch pipe I03 connecting themain reservoir supply pipe 20 to the reservoir, a one-way or check valveI04 being interposed in the pipe I03 to prevent back flow of fluid underpressure from the sanding reservoir through pipe When the piston 64 isshifted downwardly into seated engagement on the gasket seat of thegasket 33 it engages the end of a plunger I05 which in turn engages alug I06 formed on the sanding valve 62 so that when the piston 04 isseated on its gasket seat the sanding valve 62 is shifted from its upperseated position to its lower seated position. The plunger I05 carriesthereon a valve I01 of the poppet type, and a coil spring I00 isinterposed between the valve I01 and the sanding valve 02 in a chamberIt!) for.

yieldingly urgingthe valve I01 into seated position on an associatedvalve seat when the sanding valve 62 is in its upper seated position.When the valve I0! is seated, it prevents leakage of fluid underpressure therepast through a bore II2 connecting the chambers I0 and I09through which bore the plunger I05 extends. The plunger I05 is providedwith a series of axially spaced piston ring flanges III which closelyfit bore II2 so as to prevent leakage of fluid under pressure from thechamber I0 to the chamber I09 and vice versa, while valve I0! isunseated.

The sanding valve device 23 comprises a casing containing an operatingpiston II4 having at one side thereof a piston chamber II5, that isconstantly connected to the chamber I09 of the control valve mechanismI6 as through a pipe and passage H6, and having at the opposite sidethereof a chamber Ill which is constantly open to atmosphere through aport II8. Pipe I I8 is open to atmosphere through a vent port having achoke I I9 therein.

The piston II4 of the sanding valve device 23 is provided with .a stemI2I which carries a valve I22 of the poppet type. The casing of thesanding valve device 23 has two spaced walls I23 and I24 therein, thewall I23 having a central opening through which the stem I2I of thepiston extends in close-fitting slidable relation to prevent leakage offluid under pressure along the stem I2I from a chamber I25, formedbetween the Walls I23 and I24, to the atmospheric chamber II'I. nectsthe chamber I25 to a chamber I21 that is constantly charged with fluidunder pressure from the sanding reservoir 22, as by a branch pipe I28 ofthe sanding reservoir pipe I02.

The valve I22 on the piston stem I2I is normally yieldingly urged in theright-hand direction, as seen in the drawing, into seated relation on anassociated valve seat formed on wall I24 to close the port I26, by acoil spring I29 contained in the chamber I2'I and interposed between thevalve I22 and the casing.

A plurality of the sanding devices 2I are connected to the chamber I25of the sanding valve device 23, as by connecting pipes I3 I.

It will accordingly be seen that when fluid under pressure is suppliedto the piston chamber II5 of the sanding valve device 23, valve I22 isunseated and fluid under pressure is supplied therepast from the sandingreservoir 22 to the sanding devices 2I to effect sanding.

The magnet valve device I'I functions to control the exhaustcommunication for the chamber 44 at the upper side of the operatingpiston 31 of the release valve device 34 in the control valve mechanismI6. Magnet valve device I'I comprises a suitable casing containing avalve I35 of the poppet type, and an electromagnet winding or solenoidI36 effective, when energized, to actuate a plunger I31 which in turnunseats the valve I35 from an associated valve seat against the yieldingresistance of a coil spring I38. The valve I35 is contained in a chamberI29 which is constantly connected as through a pipe I4I to the pistonchamber 44 of the release valve device 34 in the control valve mechanismI6. Upon energization of the electromagnet winding I36 and unseating ofthe valve I35, communication is established past the valve I35 frompiston chamber 44 and the chamber I39 to a chamber I42 which isconstantly open to atmosphere through a port I43. Thus, as long as theelectromagnet winding I36 is energized, the chamber The wall I24 has aport I26 which con- I 44' of the release valve device.34- is vented toatmosphere through the exhaust port- I43 of the 'gagement. Suitablethrust bearings It! are pro-' vided for sustaining the axial thrust ofthe pulley lEI on the end cover II due to the force of the spring I66and also the'thrustof ion the fly wheel I45.

recesses.

magnet valve device I1 and when the electromagnet winding I36 isdeenergized the venting communication is closed.

The wheel-slip responsive deviceI8 is illustr-a-- tive of any suitabledevice for effecting energizetion of the electromagnet winding I36 ofthe magnet valve device I? instantaneously upon the slipping of avehicle wheel with which it is associated.

-As shown, the wheel-slip responsive device I8 is of the type describedand claimed in my copending application Serial No. 137,956, filed April20 '1937, and issued as Patent 2,140,620.

Briefly, wheel-slip responsive device I8 com The fly-wheel I46 issupported for rotation within the casing by a ball bearing I54 at theend of the hub portion I53, which bearing is arranged to move 'slidablyin a bore I55 of the casing,.a'nd by ano-ther'ball bearing !53 inset atthe opposite end of the hub portion'in a suitable recess formed in'theface of the fiy-wheel, which bearing is arranged to rotatably andslidably support the fiy-wheelon the shaft Ml.

Suitably fixed on the outer end of the shaft Hill-which projects throughthe end cover IiiI of the casing is a. pulley IEI having an annulargroove I62 therein for receiving an endless belt that connects the shaftto any rotary. element,

such as the wheel axle, that rotates according to "the rotation of oneof the vehicle wheels on which the brakes are applied by the brakecylinder II. The fly-wheel I46 is rotated by rotation of the shaft it?through a clutch arrangement comprising a disc Hi3 fixed to the shaft,and a coil spring I 64 so interposed between a collar or flange I55 onthe'shaft I il'and an annular shoulder I65 within the bore l52of the hubportion I53 of the fiy-wheel, as to urge the fiy-wheel I46 and the disc163' into interlocked or clutching enthe spring I04 The disc I53 and thefly-wheel M6 are interlocked by means of a plurality of spaced pairs ofcomplementary registering recesses I69 and Hit.

in the juxtaposed faces of the disc and fiy-wheel, and asteel ball I'llin each pair of complementary Any-suitablenumber of pairs of recessesI69 and Eli) may be provided, arranged in spaced circumferentialrelation radially outward from the shaft f ll. The recesses iiiil andI'lt are relatively short and curved uniformly about the axis of theshaft I41, so as to resemble somewhat the contour of a kidney bean, andvary in depth along the arc thereof with respect to the face of the discor fiy-wheelin which they are located,

being deepest at the mid-point andsloping outwardly in oppositedirections-tothe face of the disc or fly-wheeL- It will thus be seenspring Ifit the'steel balls i'iI normally seat in the that under theinfluence of deepest portion of each pair of complementary reresistanceof the spring 'It l.

fingers I15 and H6 to the casing.

cesses- I69 and I'll) so, that .thefiy-iwheelMG-and the disc- I63 areaccordingly normally interlocked for rotation together.

The compressive force 01' strength of the spring,

I64 is such as to'maintain the; fiy-wheel 7 I46 and: 5 :disc I83 ininterlocking engagement as shown,

as long as the disc does notv-idecelerate or accelerate with respect tothe fly-wheel in excess of a certain rate, corresponding for example toa ten mile per hour per second rate of retardation or 10 acceleration ofthe vehicle wheel driving the shaft. Mi. Such a high rate .ofacceleration or deceleration of thevehiclewheels will not occur duringan application of the brakes except by exceeding the limit of adhesionbetween the vehiclewheel and its associated rail-surface, that is, byslipping of the wheel. 1

When the shaft I i'l decelerates at a rate corresponding to thedeceleration of the vehicle wheel while slipping, the fly-wheel M6 tendsto overrun or lead the shaft M1 and consequently shifts rotativelyforward of its normal position with respect to the disc H33. When theshaft I M accelerates according to the rate ofacceleration of thevehicle wheel back toward a speed corresponding v to vehicle or railspeed while slipping, the fly-wheel M5 tends to under-speed or lagbehind the shaft I4? and consequently shifts rotatively backward of itsnormal position with respect to the disc I63. In'view of the steelballs- I.'I'I- interposed between 3 the disc I63 and the fly-wheel Hit,the rotative shift of the fly-wheel I 46 relative to the disc, eitherforwardly or backwardly of its normal position, causes the fly-wheel MBto be shifted axially in the right-hand direction against the yieldingThe degree of rotative shift of the fly-wheel I46 relative to the disc5% is limited to a degree which prevents the steel balls ill fromleaving the complementary recesses I68 and Iiil, as by e one or morepins (not shown) in the disc orifly wheel cooperating with arcuate slotsor grooves (not shown) in the fly-wheel or disc, in the man nersho'wn'and described in my above-mentioned copending application. 1 Theswitch device I48 of the wheel-slip responsive device I8 comprisesa pairof flexible resilient contact fingers I15 and I'M, each of which isfixed at one end to an insulating member I'll secured within the casingI at the end 50 of the hub'portion I53 of the fiy-wheel. The contactfingers I 15 and H6 are disposed in spaced parallel relation inalignment with the axis of the shaft M'L'the free ends of the contactfingers being normally disengaged from each other; ;}5 When thefly-wheel M6 is-shifted in the righthand direction, as a result ofshifting rotative'ly relative to the disc i632, the closed end of thehub portion I53 of the fly-wheel engages the free end of a resilientspringmen'lber I18, fixed at; its Qhposite end in the insulating memberIT! in alignment with the contact fingers H5 .--a nd H5, and bends itlaterally against the contact finger I35 which is, in turn, bent intocontact with the contact finger Il't. A tip I'M of insu-l latingmaterial is provided on spring member lit for preventing the groundingof the contact The pressure operated switch it functions jointly withthe switch device MB of the wheel- '70 slip responsive device I8 tocontrol energization and deenergization of the elec'tromagnet winding i35 of the magnet valve device Ill. As shown diagrammatically, thepressure switch I9 comprises a casing having a piston IBI for operatinga switch'member I82 into and out of contact with a pair of contactmembers I83, suitably carried in insulated relation on the casing; Theswitch member I82 is carried in insulated relation on a stem I84 of thepiston' I8I, and a coil spring I85 interposed between pistonIBI and thecasing yieldingly urges the piston I8I downwardly to a nected to thestraight-air pipe I4 at a point adjacent the brake valve I3 through abranch pipe I81.

The strength of the spring I85 is such that when the fluid pressureestablished in the straight-air pipe I4 and effective in the chamber I86on the piston I8! exceeds a relatively low pressure, such as five poundsper square inch, the resisting force of the spring is overcome and thepiston I 8| is shifted upwardly to effect engagement of the switchmember I82 with the contact members I83.

The electro-magnet winding I36 of the magnet valve device I! isenergized by current supplied from a suitable source, such as a storagebattery I89, which may be the storage battery for the lighting system onthe cars of the train, under the joint control of the switch device I48of the wheel-slip responsive device I8 and the pressure switch I9. Thecontrol circuit for the electromagnet winding I36 needs no descriptionfor, as

clearly seen in the drawing, the magnet winding I36, the switch deviceI48 of the wheel-slip responsive device I8 and the pressure switch I9are connected in series relation across the terminals of battery I89.

Operation of equipment The main reservoir I2 is charged to the normalpressure carried therein, as from a-fluid compressor not shown, in theusual manner. The sanding reservoir 22 is charged to the pressure in themain reservoir I2 through the branch pipe I83 and the timing reservoir24 is also correspondingly charged with fluid under pressure past thesanding valve 6?. of the control valve mechanism I8 which is in itsnormal upper seated position,

Let it now be assumed that a car or train is traveling along the roadunder power or coasting and that the equipment is conditioned as shownin the drawing, the brakes being released. To

to a degree corresponding to the position of the brake valve handle inthe application zone and fluid under pressure is accordingly suppliedfrom the straight-air pipe I4 through brake cylinder pipe I5, chamber 68of the control valve mechanism'IS, past the unseated valve piston 8!,passage 69, chamber 6?, supply passage 56, annular chamber 5I, passage52, and brake cylinder pipe I5 to the brake cylinder II. Accordingly,the fluid pressure established in the brake cylinder 1 I corresponds tothat established in the straight air pipe I4 and the brakes are thusapplied to a degree corresponding to the position of the brake valvehandle 25.

As long as the degree of application of the brakes, as determined by thepressure in the brake cylinder II is not suflicient to cause slipping oithe wheels with which the brake cylinder I II is associated, the controlvalve mechanism IE remains conditioned as shown in the drawing,

and the operator may shift the brake valve handle 25 as desired tocorrespondingly control the pressure in the brake cylinder to secureanydesired degree of application of thebrakes.

In the event, however, that a wheel on which the brakes are applied bythe brake cylinder II begins to slip due to the application of thebrakes, the wheel-s1ip responsive device I8 operates in the mannerpreviously described to close its switch device I48 which completes thecircuit for energizing the electro-magnet winding I86 of the magnetvalve device I'l, it being understood that the pressure switch I9 haspreviously been actuated into circuit-closing position due to thepressure established in the straight-air pipe I4.

Valve I35 of the magnet valve device I! is accordingly unseated toestablish the exhaust passage for venting fluid under pressure from thepiston chamber 44 above the piston 31 of the release valve device 34.Piston 31 is accordingly shifted upwardly into seated engagement on itsgasket seat and the piston chamber 44 is accordingly disconnected fromthe passage '53 and isolated at atmospheric pressure. At the sametime,the

vent valve 39 is unseated upwardly to exhaust fluid under pressure fromthe brake cylinder -Il through the exhaust port 48, and the piston M ofthe release valve device 34 cuts off communication from the supplypassage 56 to the annular chamber SI and connected brake cylinder II.

It will thus be seen that the release valve device 34 is operatedinstantly in response to the initiation of slipping of the vehiclewheels to cut ofi the further supply of fluid under pressure to thebrake cylinder II and to vent fluid under pressure at a rapid rate fromthe brake cylinder. Inasmuch as the chamber 44 above the piston 3? ofthe release valve device 34 is isolated at atmospheric pressure andbrake cylinder pressure is effective in the annular chamber 5| on thelower face of the piston 31, the piston is maintained seated on itsgasket seat until the pressure in the brake cylinder reduces below therelatively low uniform pressure of five pounds I per square inch. aspreviously explained.

The vent valve 39 of the release valve device 34 is effective whenunseated to vent the chamber "I3 at the lower side of the piston 64 ofthe reapplication valve device 35, and accordingly the piston 64 isactuated downwardly into seated relation on the gasket 33b. The valvepiston BI is thus shifted into seated relation on the annular rib seatI2 to prevent the supply of fluid under pressure from the straight-airpipe I4 through the passage 69 to the chamber 61 and supply passage 55.Also, the exhaust valve 63 is unseated and the sanding valve 82 shiftedfrom its upper seated position to its lower seated position. I l 1 Itwill be apparent that the piston 84,in shifting downwardly to seatedposition on its gasket seat, passes the passage 83 and thus causes thestraight-air pipe pressure to become efiective through the passage 83 inthe annular chamber 88 on the upper face of the piston 64. At the sametime, the isolation of the piston chamber I9 is effected by engagementof the annular rib 81 on'the piston with the gasket seat and the.unseated exhaust valve 63 maintains the piston chamber 19 atatmospheric pressure. Thus, as long as the pressure in the straight-airpipe thereafter eiiective in the annular chamber 88 on the upper side ofthe piston 64 exceeds the relatively low uniform value sufficient toovercome the force of the spring 8!, the piston 64 is maintained inseated engagement on its gasket seat.

With the sanding valve 62 seated on its lower valve seat, communicationis cut ofi between the sanding reservoir 22 and the timing reservoir 24,and communication is established past the upper valve seat through whichfluid under pressure is supplied from the timing reservoir 24 to thepiston chamber H5 of the sanding valve device 23. The piston I'M isaccordingly shifted in the left-hand direction to unseat the valve I22,which opens communication through which fluid under pressure is suppliedfrom the sanding reservoir 22 to the sanding devices 2|, to causesanding of the rails adjacent the slipping wheels as long as the valvein is unseated.

The time that the valve I22 is unseated is reservoir 24 and size of thechoke H9 may be so related as to maintain the valve I22 unseated for anydesired length of time, as for example, the length of time required tobring 'a car or train to a complete stop, or a shorter interval of time.In anyevent, when the pressure in the piston chamber H5is reducedsufiiciently due to the escape of fluid under pressure through the chokeH8, the spring I25? becomes effective to reseat the valve 22 and thuscut oil. the further supply of fluid under pressure from, the sandingreservoir 22 to the sanding devices 2!, thus terminating the sanding oithe rails.

Assuming that the retardingforce on the slipping wheels is relaxedcorrespondingly to the rapid reduction in brake cylinder pressure, thevehicle wheels cease deceleration and begin to accelerate back toward aspeed corresponding to vehicle or rail speed when the brake cylinderpressure has reduced a relatively small amount fromthat which initiatedthe slipping. Since a slipping vehicle wheel accelerates very rapidlyback toward vehicle or rail speed once it starts such acceleration, itwill be apparent that the slipping-vehicle wheels will return to a speedcorresponding to vehicle or rail speed before the pressure in the brakecylinder H is reduced sufficiently to permit the spring 45 of therelease valve device to actuate the piston 31 and vent :valve 39 thereofdownwardly to reseat the vent valve 39 and reestablish the supplycommunication to the brakecylinder ll. It will thus be seenthatreapplication of the brakes associated with a wheel which has slipped isheld off or prevented until the wheel has fully returned to vehicle orrail speed.-

In some instances, it may happen that the reduction of the retardingforce on a slipping wheel is not eifected'correspondingly to thereduction in brake cylinder pressure and that a considerable amount ofreduction in brake cylinder pressure is required before the retardingforce, is reduced. In such cases, the-vehicle wheel may reduce to arelatively low speed while slipping, and thus the time interval betweenthe initiationof slipping and the return to vehicle'or rail speed may begreater. In order, therefore, to' prevent the immediate: and: rapidrestoration of pressure in the brake cylinder, in such instances, whichmight drawing to reestablish the supply communication to the brakecylinder 1 l, fluid under pressure can be resupplied to the brakecylinder from straightair pipe l4 only at the restricted rate determinedby the size of the choke element 1 I result in recurrence of slippingof. the wheels,

Thus,

It will be seen that the reestablishment of the supply communication tothe brake-cylinder ll tendsto cause a reduction of the pressure in thestraight-air pipe I4 due to the flow of fluid under pressure from thestraight-air pipe through the e choke H and brake cylinder pipe l5 tothe brake cylinder l I. Accordingly, the brake valve I3 functionsautomatically upon the restorationof the release valve device 34 to itsnormal position, to maintain the pressure in the straight-air pipe 1 4.at a pressure corresponding to the position of the brake valve handle25, so that the ultimate degree of pressure reestablished in the brakecylinder, H corresponds to the position ofthe brake valve handle 25.However, due to the restricted rate of supply of the brake cylinder Hthrough thechoke H, the. pressure in the brake cylinder H .is'restored'at a slow rate and thus ".suflicient' pressure to cause recurrence ofwheel train reduces thedegree of application of the brakes, asthe speedof the car or train reduces 4 inorder to cause retardation of the trainat av more. uniform rate throughout the stopping distance. Accordingly,assuming thatthe operator shifts the brake valve handle 25 towardsrelease position from the initial position in the applica lowing returnof the slipping wheel to vehicle or rail speed will be less than thatwhich initiated the slipping of the wheel, thus further minimizing vping wheel, as when it ceases to decelerate and begins to accelerateback toward a speed corresponding to vehicle or rail speed. When thevehicle wheel ceases to .decelerate and begins to accelerate whileslipping, the fiy-Wheel MB of tion zone, it Willbe apparent that thepressure ultimately restored in the brake cylinder H folthe wheel-slipresponsive'device I8 is returned v momentarily to its normal position,in which the contact fingers H5 and ITS-of the switch device Hi8 areseparated, thus effecting deenergization her 5! on the lowerface of thepiston 3'lfof the release valve device 34 maintains the piston in seatedrelation of its gasket seat, such momentary separation of the contactfingers I15 and H6 of the wheel-slip responsive device I8 is withouteffect. Furthermore, as long as the vehicle wheel is accelerating backtoward a speed corresponding to vehicle or rail speed, while slipping,at a rate in excess of ten miles per hour per second, the contactfingers I I5 and I16 remain in engagement. Thus, while the vehicle is soaccelerating, the valve I35 of the magnet valve device I'I continues toestablish the venting communication for the chamber 44 above the piston31 of the release valve device 34.

It will thus be seen that the wheel-slip responsive device I8 is in thenature of a trigger mechanism which sets the control valve mechanism Itinto operation, the valve mechanism It functioning automatically, onceit is set into operation, independently of further operation of thewheel slip responsive device I8 during any one slipping cycle.

In the event that a vehicle wheel should again begin to slip uponreapplication of the brakes thereon in the manner previously described,the wheel-slip responsive device I8 again operates to vent the pistonchamber 44 of the release valve device 34 and cause the release valvedevice 34 to cut off the supply of fluid under pressure to the brakecylinder and vent fluid under pressure rapidly therefrom. Since in suchcase, the piston 64 of the reapplication valve device 35 is still in itslower seated position on the gasket seat, the unseating of the ventvalve 39 is ineffective to cause operation of the reapplication valvedevice 35. However, upon the subsequent reseating of the vent valve 39following sufficient reduction of brake cylinder pressure, thereapplication valve device 35 is conditioned as before to restrict therate of resupply of fluid under pressure to the brake cylinder I I.

Obviously, when the timing reservoir 24 is of sufficient capacity toinsure the continued sanding of the rails throughout a brakeapplication, the recurrence of wheel slipping during any one applicationis exceedingly unlikely.

When the car or train is brought to a complete stop, the operator mayshift the brake valve handle 25 to increase the pressure in thestraight-air pipe and thus in the brake cylinder I I to increase thedegree of application of the brakes, as desired, to hold the car ortrain on any grade that may be encountered in service.

When it is desired to release the brakes prior to again starting thetrain, the operator merely shifts the brake valve handle 25 to releaseposition, thus completely venting fluid under pressure from thestraight-air pipe I 4 and connected brake cylinder II to atmosphere andefiecting the complete release of the brakes.

It will be apparent that when the pressure in the annular chamber 88,acting to maintain the piston 54 of the reapplication valve device 35 inits lower seated position on its gasket seat, is reduced sufficientlydue to the reduction of the pressure in the straight-air pipe I4, thespring 8| becomes effective to shift the piston 64 upwardly to itsnormal position unseating the valve piston 6| from the annular rib seat12 to restore the communication through the passage 69 between thechambers 66 and 61, thus restoring the valve mechanism It to its normalcondition for another operation thereof. When the piston 64 of thereapplication valve device 35 is shifted upwardly to its normalposition, the exhaust valve' 63 is reseated to cut oifthe exhaustcommunication for the chamber I9 and, at the same time, the sandingvalve 32 is returned upwardly to its upper seated position restoring thecharging communication between the sanding reservoir 22 and the timingreservoir, so that the timing reservoir 24 is again recharged to thenormal pressure carried therein.

It will be apparent that if the wheel-slip responsive device It isassociated with a traction wheel and axle unit and excessive propulsionforce is applied to the traction wheel upon starting of the car or trainsufiicient to cause racing thereof, the contact fingers I 75 and I 16 ofthe switch device I48 thereof will be shifted into engagement with eachother. However, with the brakes released, the pressure switch l@ is incircuit-opening position so that the closing of the switch device I48under such condition is ineffective to cause energization of the magnetwinding I36 of the magnet valve device I'I. tion of current from thebattery I89 is thus avoided.

In the case of a train brake equipment, it shoul be understood that thedifferent brake cylinders along the length of the train on the variouscars are controlled by equipment duplicating that described for thebrake cylinder II and, therefore, while the brake valve I3 is effectiveunder the control of the operator to control the application and releaseof all the brakes throughout the train, the various control valvemechanism It and sanding valve devices 23 local to each brake cylinder,are automatically controlled to provide individual control of one ormore wheel and axle units in response to the slipping of the wheelsthereof.

Summary Summarizing, it will be seen that I, have disclosed a fluidpressure brake equipment for vehicles, such as railway cars and trains,operative to prevent sliding of the vehicle wheels. The inventioncomprises essentially a control valve mechanism including a releasevalve device, a reapplication valve device, and a sanding valve adaptedto be set in operation by a suitable wheelslip responsive device inresponse to the initiation of slipping of the vehicle wheels. Therelease Unnecessary consumpvalve device functions automatically to cutoff 1 the supply of fluid under pressure to'the'brake cylinder and torapidly vent pressure from the.

brake cylinder and to continue to vent fluid under pressure from thebrake cylinder as long as the pressure therein'exceeds a certain uniformlow pressure such as five pounds per square inch. The reapplicationvalve device is automatically operated in response to the operation ofthe release valve device to prevent more than a restricted rate ofresupply of fluid under pressure to the brake cylinder when the releasevalve device is restored to its normal condition. The reapplicationvalve device is automatically held in its rate restricting position,once it is operated thereto, until the brakes are released.

The sanding valve is operated by the reapplication valve device toinitiate sanding of the rails, the sanding being automatically timed toterminate after a certain uniform time, preferably suificient to bringthe train to a complete stop.

While I have illustrated and described only one embodiment of myinvention, it will be apparent that various omissions, additions, ormodifications may be made therein without departing from the spirit ofmy invention. For example, it will be apparent that, if desired, thesanding valve 62 of the control valve mechanism I6 may be brakes,comprising fluid pressure operated valve means including a movable.abutment having a normal position inwhich it is subject on one side tothe pressure in the brake cylinder and on the opposite .side to thepressure in a chamber, means for charging said chamber'gwith fluid underpressure at a sumciently rapid rate when fluid under pressure is.supplied to the brake. cylinder to-prevent movement of the movableabutment out of its normal position, said movable abutment being shiftedout of its normal position to a different position in response to asudden reduction of pressure-in said chamber during an application ofthe brakes, and being efiective in its said dilierent position toprevent the further supply of fluid under pressure to said chamber sothat it is maintained thereafter in its said different position by brakecylinder pressure as long as the pressure in the brake cylinder exceedsa certain uniform pressure, said valve means being effective when thesaid abutment is in its said different position to prevent the supply offluid under pressure'to the brake cylinder and to vent'fluid underpressure'from the brake cylinder. r

2. A valve mechanism for use in vehicle brake equipment of the typehaving a brake cylinder to whichfluid under pressure is supplied toeffect der and said chamber whereby, upon the supply of the fluid underpressure to the brake cylinder, said chamber is charged with fluid underpressure supplied to the brake cylinder at a sufliciently rapid ratethat said movable abutment is unresponsive to the pressure of fluidsupplied to the brake cylinder, said movable abutment being operative inresponse to a sudden reduction of pressure in the chamber to a difierentposition in which said chamber is isolated from the brake cylinder andthereafter so responsive to the pressure in the brake cylinder as to bemaintained in,

its said difierent position as long as the pressure in the brakecylinder exceeds a certain'uniform pressure, said valve means beingefiective when the abutment is in its said diflerent position to preventthe supply of fluid under pressure to the brake cylinder and to ventfluid under pressure from the brake cylinder.

3. A valve mechanism normally providing a to the pressure in thecommunication and in achamber whereby said abutment is unresponsive tothe pressure in the communication, said mova- .,5. Avalve ferentposition.

ble abutment being operative from its normal position to a differentposition in response to a sudden rapid reduction of pressure in saidchamber, means effective when the abutment is in its said'difierentposition for isolating said cham-v ber, and means effectivewhen the abutment is in its said diiierent position for venting fluidunder pressure from said chamber whereby said abutment is maintained inits said different position by the pressure in the communication as longas the pressure in the communication exceeds a certain uniformpressure-said valve mechanism being effective when the abutment is inits said different position to close the said'communication: 4. A valvemechanism including valve means normally effective to providecommunication through which fluid under pressure may be sup plied at arelatively unrestricted rate and a movable abutment foreffectingoperation of said i valve means to a different position in which it iseffective to provide communication through which fluid under pressuremay be supplied at only a relatively restricted rate, said abutmenthaving a normal position in which it is subject to the opposing.pressures of the fluid in the said communication and in a chamberwhenfluid unber toa different position to cause operation of the saidv valvemeans to its different position, means for isolating said chamber whenthesaid abutment is in its said different position, and

means efiective'to vent fluid under pressure from the said chamber whenthe'said abutment IS in its said different position whereby the pressureI ing a communicationztherein including two parallel-related passages,one of which is of relatively large flow area and the other of which isof relatively small flow area,'a valve for controlling the flow of fluidunder pressure through the relatively large passage, a movable abutmentfor operating said valve, resilient means normally effective to urgesaid abutment to a position in which it operates the said valve to aposition in which the relatively large communication is open, saidabutment being subject in opposing relation to the pressure in thecommunication and in a chamber supplied-with fluid under pressure fromthe communication whereby said abutment is mechanism comprising a casinghav -v normally unresponsive to the pressure of fluid sure in saidchamber when the abutment is in its normal position whereby saidabutment is shifted by the pressure of the fluid in the communication toa difierent position in which the said chamber is isolated from the saidcommunication, and an exhaust, valve effective to vent fluid underpressure from said chamber independently of said last means when thesaid abutment is in its said different position whereby said abutment ismaintained in its said different position by the pressure in the saidcommunication as long as the pressure in the communication exceeds acertain uniform pressure, said valve being operated to a position forclosing the relatively large passage when the said abutment is in itssaid difand the other of said valve devices having a normal position inwhich it permits a relatively un-- restricted-flow of fluid underpressure through the communication and a different position in which itrestricts the flow of fluid under pressure through such communication,said one valve device being effective when operated to its difierentposition to effect operation of the other of said valve devices to itsdifierent position.

' 7. A valve mechanism comprising a casing having a communicationthrough which-fluid under pressure may be supplied, and twoserially-related valve devices for controlling the'flow of fluid underpressure through the communication, one of said valve devices having anormal position in which said communication is open and a differentposition in which said communication is closed, and the other of saidvalve devices having a normal position in which it permits a relativelyunrestricted flow of fluid under pressure through the communication anda different position in which it restricts the flow of fluid underpressure through such communication, said one valve device beingeffective when operated to its difierent position to efiect operation ofthe other of said valve devices to its difierent position, and meansefiective when the said other valve device is in its said differentposition to maintain it in its said different position after the saidone valve device is returned to its normal position.

- 8. A valve mechanism comprising a casing having a communicationthrough which fluid under pressure may be supplied, and twoserially-related valve devices for controlling the flow of fluid underpressure through the communication, one of a l-asset vice beingeifective when operated to its different position to eflect operation ofthe other of said valve devices to its different position, and meanseffective when the said other valve device is operated to its saiddifferent position for causing it to be maintained in its said differentposition as long as the pressure in the said communication exceeds acertain uniform pressure.

9. A valve mechanism comprising a casing having a communication throughwhich fluid under pressure may be supplied, and two serially-relatedvalve devices for controlling the flow of fluid under pressure throughthe communication, one of said valve devices having a normal position inwhich said communication is open and a different position in which saidcommunication is closed, and the other of said valve devices having 2.normal position in which it permits a relatively unrestricted flow offluid under pressure through the communication and a different positionin which it restricts the flow of fluid under pressure through suchcommunication, said one valve device being efiective when operated toits difierent position to effect operation of the other of said valvedevices to its different position, said other valve device being soconstructed and arranged as to be maintained in its different positionby the pressure of .the fluid in the said communication, even though thesaid one valve device returns to its normal position, as long as thepres sure in the said communication exceeds a certain uniform pressure.

CLYDE C. FARMER.

